The present invention relates to ultrasound guided prostate needle biopsies, and more particularly, to ultrasound guided prostate needle biopsies based on a biomechanical model of the prostate from magnetic resonance imaging data.
Prostate cancer is typically diagnosed by using a transrectal ultrasound (US) guided biopsy, which is typically prescribed as a result of an elevated prostate-specific antigen (PSA) level or due to the detection of a palpable nodule during a digital rectal examination (DRE). The introduction of image guided biopsy using US has substantially increased the accuracy of biopsy, as compared with the very poor accuracy of performing blind biopsy, resulting in transrectal US guidance becoming the universally accepted methodology for prostate biopsy. However, while transrectal US guided prostate biopsy is a clinically accepted methodology, the overall procedure results demonstrate a low sensitivity of approximately 60%, with only 25% positive predictive value. Consequently, repeat biopsies are often required for a definitive diagnosis. For example, in more than 20% of cancer studies, there is a requirement of more than one biopsy session to reach a diagnosis decision.
Magnetic resonance (MR) imaging can clearly depict not only the prostate gland, but also its substructure including the central, transitional, and peripheral zones. T2-weighted MR images can visualize nodules in the peripheral zone of the prostate. Localizing the tumor foci and the peripheral zone with MR imaging prior to the prostate biopsy may increase the overall cancer detection rate. Localizing the tumor foci and the peripheral zone with MR imaging before the prostate biopsy may increase the overall cancer detection rate. In addition, functional information can be acquired with techniques like diffusion weighted imaging (DWI), dynamic contrast imaging (DCE), and chemical shift imaging (CSI) to further characterize the prostatic tumor tissue. Using this information during US-guided biopsy can improve the sensitivity of the biopsy procedure. For example, in a known technique, endorectal MR imaging findings of suspected tumor foci were used to guide the placement of needles during transrectal US-guided biopsy. By localizing suspected tumor lesions or targets on the endorectal MR image and by visually correlating the locations to US images during transrectal US-guided biopsy, the accuracy of the transrectal US-guided biopsy, aided by using MR imaging, was 67% in a study of 33 patients. The data for this study underwent a tedious visual inspection, which cannot be implemented as a clinical routine.
There exists a need to enhance the sensitivity in detecting malignant lesions during a prostate biopsy procedure.